@Muse - ### Modifications Made
1. **Operating Voltage Reduced to $1.5\text{ V}$:**
- **Threshold Voltages ($V_{to}$):** Decreased transistor threshold magnitudes from $1.0\text{ V}$ and $2.0\text{ V}$ down to $\pm 0.4\text{ V}$, enabling full differential switching, gate drive, and subthreshold margins at $V_{DD} = 1.5\text{ V}$.
- **Reference Divider:** Replaced the three stacked diode-connected NMOS transistors with a dedicated high-impedance divider (#Rtop, #Rmid, #Rbot) using $1\text{ M}\Omega$ resistors. This ensures true $\frac{1}{3}V_{DD}$ and $\frac{2}{3}V_{DD}$ taps regardless of supply voltage down to $1.5\text{ V}$.
2. **Ultra-Low Current Consumption:**
- **External Timing Network:** Increased timing resistors #RA and #RB from $1\text{ k}\Omega$ to $100\text{ k}\Omega$ and scaled the timing capacitor #C1 down to $100\text{ pF}$. This cuts the branch charging current from over $3\text{ mA}$ down to approximately $7.5\text{ }\mu\text{A}$.
- **Internal Transistor Sizing:** Reduced the channel widths across the comparator stages and digital gates down to $10\text{ }\mu\text{m}$ (from $100\text{ }\mu\text{m}$–$300\text{ }\mu\text{m}$). This minimizes dynamic switching energy and gate leakage without sacrificing switching speed.
- **Supply Connection:** Eliminated the series diode drop and unnecessary switch resistance to deliver the full $1.5\text{ V}$ directly to the rails.
